code: def test_covered_pairs(self):
      p1 = lambda x, target=None: frozenset((1,))  # noqa: E 731
  
      self.block_learner.blocker.predicates = (p1,)
      cover = self.block_learner.cover(
          self.block_learner, [("a", "b")] * 2
      )
  
      assert cover[p1] == {0, 1}
  
file_path: dedupe/tests/test_training.py
imports: import unittest
  import dedupe
  import dedupe.branch_and_bound
  import dedupe.training
label_desc: Use image node_id 4 for calling the TrainingTest obj's underlying member method code with example usage: obj.test_covered_pairs() without return types